I assume this can be fixed - but the methods I've tried haven't worked (I've tried debranding via the engineering menu, and swapping to the tmobile network profile)
Is there anything else I should try?

Unfortunately, LG Optimus 7 does not support AWS, hence it will not support 3G neither on T-Mobile USA nor Wind Mobile or Mobilicity (it will fall back to GSM/EDGE modes on T-Mobile and will always be in Wind Away zone roaming through Rogers if you were to use Wind Mobile SIM card).

Not to stop you short, but just a heads up I guess.

If you go into the MFG settings to change the network profile thare are a couple that show "TMU_US" thought I'm not sure if that's even TMobile or what carrier that would be or even which one to try. But good luck.

I saw that thread before hand, and I was anticipating the 3g problem (a tmobile rep had told me this as well)

My issue is making phone calls ATM. everyone else says when you insert a foreign sim, it asks for an unlock code - which mine hasn't done yet. I did buy the phone used on ebay (the seller claimed it was unlocked).

Regardless - right now, it says invalid sim. I inserted it with the notched corner UP

I have a Telus LG Optimus 7 phone, bought an unlock code on eBay for $10. When going down to US I use a TMO SIM card, and I can confirm that phone works perfectly for 2/2.5G (GSM/EDGE), and doesn't work with TMO 3G (which is AWS, same as Wind Mobile and Mobilicity, like someone mentioned above). But luckily for me TM has a $2/day plan which offers unlimited calls/text/2G internet, which makes it perfect for 1-2 day intermittent trips across the border, EDGE speeds are just enough to have my e-mails coming and maps working. It would support full 3G on AT&T, but they don't have any good prepaid data plans - the only one they could offer was 100 mb for $20, which expires in 7 days.

are you sure that there's no way to change settings in the engineering menu to make it work with Tmo's 3g?

I'm absolutely certain - you can manually switch between supported frequencies: WCDMA 850 MHz, WCDMA 900 MHz, WCDMA 1800 MHz and WCDMA 1900 MHz, but the phone has no support for AWS 1700/2100 (unlike regular WCDMA, when uplink and downlink use channels from the same band, AWS is also using different band for upstream and downstream).

Quote:

Originally Posted by evilgenius31

Also - what do I need to do to update my optimus to the new build of wp7?

When you say "new build" what exactly do you mean? Which build do you currently have? Does Zune tell you that you have latest firmware?

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